Well if you just google you simple could find the below statement posted late august 31st by PMDG on the PMDG forum ( meant as september update )
For you convenience i will quote the part from the link
“ The 737 looks absolutely sumptuous in MSFS and I am pretty sure we will start showing her to you this month…”
It was mentioned
“ The 737 looks absolutely sumptuous in MSFS and I am pretty sure we will start showing her to you this month…”
They have since closed the topic and removed many posts of users in the thread. It looks like it got delayed, nothing surprising when they said “prety sure”, so it was not a certainty.
We will just have to wait a little longer.
It will be released this Quarter!
It’s really looking nice, I’ll have a better look when I’m back at my PC. They did also mention a new price structure, “to make it cheaper to add a PMDG plane to your hangar”. This is good to hear too.
Super !!! Hope it comes sooner then later
wow, in this year
This will be the first add on plane that I buy. Might grab the DC-6 after that.
Wow, Wow, Wow, Wow, Wow… incredible!! I was waiting for this so long. The release in this year, finally. at Christmas, maybe? hype increasing even more…
Now, we only have to wait to hear something about Fenix simulations and their good-looking A320… It would be great if they release their A320 in this year too.
I am calling it now… $99.99. I am ok with that, even $150 if it all works no ILS issues etc which CAN plague all planes in one form or another
Posted today on their forums, early morning.
I am so excited!!!
For more info: [01OCT21] Let's start 4Q21 with some juicy 737 previews, shall we? - PMDG Simulations
Look amazing from exterior. I cannot wait to see more cockpit photos beside the three went public since last year.
And yes, I cannot wait to fly this plane 737NG in American Airlines, Southwest Airlines and Alaksa Airlines colors.
I fly this plane and I like it, too. Flying this plane is a little bit more challange than Airbus or Boing. For me the realistic feeling is very good. Documentation is best.
updated title accordingly
I much prefer the general title something like: “PMDG Boeing 737NG” to focus on everything relates to this PMDG airplane for MSFS, then you don’t have to change title again when something happen sooner or later than that Q4/2021. Just my opinion though! 
I’ll keep it for today as a lot of people probably don’t know about the update, but yeah I’ll change it to something more general soon
Love seeing the update, finally. Glad they took the road to communicate (unlike a few others). Always helps! This bird looks amazing.
Looking forward to this!! Soooo happy when I get my hands on it.
However, I expect that the plane might not be 100% feature complete yet when it is released - with further updates depending on SDK progress. But I think, I´d be fine with that, too.
Regarding price: I am eligible for the discount as I bought the last 737 on P3D, but I think it could maybe hit around 79 USD…? First thought was even 59 USD, but that´s rather unlikely. If quailty can keep up with P3D, it would also be worth 99 USD, but as they now might target a bigger audience, I think 79 might be a sweet spot… let´s see.
2021 Q4 possibly, maybe, likely, so 1st of January it is then. 
Is that 737MAX? The winglets look like it is from MAX. Please enlighten me.
